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Package leaflet: Information for the patient

Pentazocine 50 mg
Capsules, hard
(pentazocine hydrochloride)



Read all of this leaflet carefully before you start
taking this medicine because it contains
important information for you.
• Keep this leaflet. You may need to read it again.
• If you have any further questions, ask your doctor
or pharmacist.
• This medicine has been prescribed for you only.
Do not pass it on to others. It may harm them,
even if their signs of illness are the same as yours.
• If you get any side effects talk to your doctor or
pharmacist. This includes any possible side effects
not listed in this leaflet. See section 4.



What is in this leaflet:
1. What Pentazocine is and what it is used for
2. What you need to know before you take Pentazocine
3. How to take Pentazocine
4. Possible side effects
5. How to store Pentazocine
6. Contents of the pack and other information
1. What Pentazocine is and what it is used for
Pentazocine belongs to a group of medicines called
opioid analgesics. These are strong pain killers that are
used to relieve moderate to severe pain.
2. What you need to know before
you take Pentazocine
Do not take Pentazocine if you:
• Are allergic to pentazocine, or any of the other
ingredients of this medicine (listed in section 6)
• Have breathing problems for example, respiratory
depression and/or shallow breathing (which may
lead to blue lips), chronic bronchitis (coughing up
a lot of phlegm) or asthma
• Have a history of alcohol abuse
• Are recovering from a head injury, or you have a
condition which causes increased pressure on the
brain. Symptoms include severe headaches, being
sick, drowsiness or blurred vision
• Have heart failure or suffer from breathlessness
and swollen ankles
• Have porphyria (a genetic disease that can cause
skin blisters, abdominal pain and brain or nervous
system disorders).
Warnings and precautions
Talk to your doctor or pharmacist before taking
Pentazocine if you:
• Are taking a monoamine oxidase inhibitor
(MAOI, a medicine used for depression
e.g. phenelzine, isocarboxazid) or you have
taken one within the last 14 days
• Have a rare tumour of the adrenal glands called a
phaeochromocytoma. This may cause headaches,
sweating, palpitations, flushing of the face and
pains in the chest or stomach
• Have recently had a heart attack
• Have high blood pressure
• Have severe kidney or liver disease, or you are
elderly. You may need a lower dose
• Have epilepsy

• Have a history of drug abuse, or you are addicted to
opiate pain killers such as morphine or diamorphine
• Are being treated for an underactive thyroid gland
• Have a condition which affects your adrenal glands
• Have an enlarged prostate gland and have
difficulty urinating
• Suffer from an inflamed bowel or other gut disorders
• Are a smoker (the effect of Pentazocine may
be decreased)
• Have been regularly taking other pain relieving
medicines for longer than three months, especially
if you are suffering from headaches or headaches
have become worse.
Other medicines and Pentazocine
Tell your doctor or pharmacist if you are taking,
have recently taken or might take any other
medicines, especially any of the following:
Other strong pain killers (e.g. morphine,
diamorphine, naloxone)
• Phenothiazines (used to treat mental disorders,
e.g. chlorpromazine, thioridazine)
• Monoamine oxidase inhibitors (see Warnings
and precautions)
• Doxapram (used to stimulate breathing).
Pentazocine with alcohol
Do not drink alcohol whilst taking this medicine.
Pregnancy and breast-feeding
If you are pregnant or breast-feeding, think you may
be pregnant, or are planning to have a baby, ask your
doctor or pharmacist for advice before taking this
Driving and using machines
Pentazocine may cause sedation. If affected you
should not drive or use machines.
The medicine can affect your ability to drive as it may
make you sleepy or dizzy.
• Do not drive while taking this medicine until you
know how it affects you.
• It is an offence to drive if this medicine affects your
ability to drive.
However, you would not be committing an offence if:
• The medicine has been prescribed to treat a medical
or dental problem and
• You have taken it according to the instructions
given by the prescriber or in the information
provided with the medicine and
• It was not affecting your ability to drive safely
Talk to your doctor or pharmacist if you are not sure
whether it is safe for you to drive while taking this
Pentazocine contains sodium metabisulfite, which
may rarely cause severe hypersensitivity reactions
and bronchospasm
3. How to take Pentazocine
Always take this medicine exactly as your doctor or
pharmacist has told you. Check with your doctor or
pharmacist if you are not sure.
Swallow the capsules whole with a full glass of water.
The capsules should be taken after meals. Do not chew
or crush the capsules. Your doctor will decide how
much Pentazocine you should take. This will depend
on your condition and the severity of your pain.
The recommended dose is:



This leaflet was last revised in: October 2014



happy or sad • eyesight changes • chills • lack of sexual
desire and impotency (failure to maintain an erection)
• hypothermia (low body temperature)
Reporting of side effects
If you get any side effects, talk to your doctor
or pharmacist. This includes any possible side
effects not listed in this leaflet. You can also
report side effects via the Yellow Card Scheme at By reporting side
effects you can help provide more information
on the safety of this medicine.
5. How to store Pentazocine
Keep this medicine out of the sight and reach
of children.
Store below 25°C.
Blister packs: Store in the original package in order
to protect from light and moisture.
Bottle packs: Keep the bottle tightly closed in order
to protect from light and moisture.
Do not use pentazocine after the expiry date which
is stated on the container after 'EXP'.
The expiry date refers to the last day of that month.
Do not throw away any medicines via wastewater or
household waste. Ask your pharmacist how to throw
away medicines you no longer use. These measures
will help protect the environment.
6. Contents of the pack and other
What Pentazocine Capsules contain
The active substance is pentazocine hydrochloride.
Each capsule, hard contains 50 mg pentazocine
The other ingredients are microcrystalline cellulose,
pregelatinised maize starch, calcium hydrogen
phosphate dihydrous sodium metabisulfite, sodium
lauril sulfate, colloidal anhydrous, silica, magnesium
stearate, croscarmellose sodium. The capsule shell
contains yellow iron oxide (E172), red iron oxide
(E172), titanium dioxide (E171), black iron oxide (E172)
and gelatine. The printing ink also contains Shellac
and titanium dioxide
What Pentazocine Capsules look like and contents
of the pack
Your medicine comes as a hard grey/orange capsule,
marked 'PT50' on one side and 'G' on the other side
printed in white ink.
Pentazocine is available in containers or blister packs
of 5, 7, 10, 14, 15, 20, 21, 25, 28, 30, 56, 60, 84, 90, 100,
112, 120, 168, 180, and 500 capsules.
Not all pack sizes may be marketed.
Marketing Authorisation Holder
Mylan, Potters Bar, Hertfordshire, EN6 1TL,
United Kingdom.
Generics [UK] Limited, Potters Bar, Hertfordshire,
EN6 1TL, United Kingdom.
Gerard Laboratories, 35/36 Baldoyle Industrial Estate,
Grange Road, Dublin 13, Ireland.


Adults - One 50 mg capsule every four hours. If more
pain relief is needed your doctor may increase your
dose to two 50 mg capsules every three to four hours.
The maximum dose is 600 mg a day.
Use in children and adolescents
Other forms of this medicine may be more suitable
for children, ask your doctor or pharmacist.
Older people or patients with kidney or liver
problems- Your doctor may give you a lower dose.
If you take more Pentazocine than you should
Contact your doctor or nearest hospital emergency
department immediately. Take the container and
any remaining capsules with you. Signs of overdose
include drowsiness, shallow breathing, low or high
blood pressure, fast heartbeat, hallucinations
(seeing things that are not there) coma or fits.
If you forget to take Pentazocine
Take the next dose at the usual time. Do not take
a double dose to make up for a forgotten dose.
If you stop taking Pentazocine
Do not take your capsules more often or for longer than
your doctor advises. Too much Pentazocine can be habit
forming. This is called dependence. If you stop taking
your medicine suddenly it can cause withdrawal effects
such as sweating, fever, weakness and muscular pains.
Your doctor will help stop your medicine gradually to
avoid you having these withdrawal symptoms.
If you have any further questions on the use of this
medicine, ask your doctor or pharmacist.
4. Possible side effects
Like all medicines, this medicine can cause side effects,
although not everybody gets them. If they occur, they
are likely to be mild. However, some may be serious
and need medical attention.
If the following side effects occur, stop taking the
capsules immediately and contact your doctor:
• sore throat, fever, severe chills and mouth ulcers.
This can be due to a lack of white blood cells called
granulocytes (agranulocytosis)
• swelling of the face, lips, tongue or throat, difficulty
in swallowing or breathing, skin rash or itchy
flushed face (allergic reaction)
• blood changes such as a reduction in white blood
cells which makes infection (with signs such as
fever) more likely
• a serious skin reaction called toxic epidermal
necrolysis. This is rare; symptoms include loss of
the outer layers of skin and reddening of the skin.
Other possible side effects are: • light-headedness,
dizziness • feeling sick, vomiting, constipation • feeling
drowsy • sedation • fainting • sweating • headache
• dry mouth • pins and needles • ureteric or biliary tract
spasm causing abdominal cramps • urinary retention
(difficulty passing water) • itching or flushing of the
skin • rapid heartbeat or slower heartbeat • palpitations
• increased pressure on the brain • slow or shallow
breathing • collapse due to very low blood pressure
• short-lived hypertension (high blood pressure)
• altered contractions of the womb • muscle tremor
• grand mal convulsions (seizures) • mood changes,
difficulties sleeping, nightmares, thought disturbances,
disorientation, confusion, hallucinations (sensing things
that are not real e.g. seeing things) • extremes of feeling

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